25亿，386亿，5410亿怎么说？

two billion and five hundred million / two and a half billion
thirty eight billion and six hundred million
five hundred and forty one billion

25亿 two point five billion
386亿 thirty-eight point six billion
5410亿 five hundred and forty-ne billion

billion就是“十亿”的意思。

two billion fifty million
thirty eight billion sixty million
five hundred and forty one billion

2,500,000,000 2.5 billion twe point five billion
38,600,000,000 38.6billion thirty eight point six billion
541,000,000,000 541billion five hundred and forty one billion